Closed-Form Study of Undetected Range Errors Induced by Ionospheric Anomalies for GAST-D GBAS

Abstract

Located at heights between approximately 50 km and 1000 km, the ionosphere is a shell of dispersive medium that contains electrons and electrically charged atoms (Misra & Enge, 2004). As global positioning system (GPS) signals travel through the ionosphere, they experience a delay, which is proportional to the density of total electron content. A ground-based augmentation system (GBAS) augments existing GPS signals by broadcasting differential corrections and integrity information to enable precision approaches for aircraft (Hoffmann & Walton, 2018). Under nominal conditions, the ionospheric delay is partly eliminated by differential corrections, and residual ionospheric errors caused by spatial decorrelation between the ground and aircraft are bounded by the integrity parameter σ vig (Chang et al., 2021). However, in the case of an ionospheric anomaly, the spatial decorrelation